Acute Asthma Exacerbation (Adults) 🫁

• Scope: acute asthma attack in adults (and adolescents aged 16+). Children under 16 are out of scope here.
• Primary reference: BTS/SIGN Asthma Guideline Quick Reference Guide (SIGN 158, Jul 2019), acute asthma in adults (PDF pp. 17–18). Irish practice: NCEC National Clinical Guideline No. 14 (2015), developed with the HSE National Clinical Programme for Asthma (update underway).
• NCEC No. 14 was largely adapted from earlier BTS/SIGN / GINA guidance, so thresholds align closely. Prefer local hospital protocols where they refine ICU or IV pathways.
• Classify severity early using PEF (% best, or % predicted if recent best unknown) plus clinical features. Treat immediately; do not delay therapy for investigations.

• ABCDE. Look for life-threatening features first: silent chest, cyanosis, poor respiratory effort, arrhythmia, hypotension, exhaustion, altered consciousness, collapse.
• Measure SpO₂, respiratory rate, heart rate, ability to speak in sentences/phrases/words, accessory muscle use, and auscultation. None of these alone is specific; their absence does not exclude a severe attack (BTS/SIGN).
• Record PEF (or FEV₁ if available) as % of previous best (most useful); use % predicted only if best is unknown. Prefer the same type of peak-flow meter where possible.
• History: usual controllers/relievers, recent oral steroids, previous ICU/near-fatal asthma, hospital/ED attendances, triggers (infection, allergen, NSAID, beta-blocker), smoking, pregnancy, adverse psychosocial factors (severe asthma + psychosocial risk factors → higher risk of death).
• Do not delay oxygen or bronchodilators while waiting for PEF if the patient is too breathless to perform it.

• Grade by the single worst feature present. Any one criterion is enough (e.g. RR ≥25 alone = acute severe even if PEF is higher).
• Life-threatening features apply in a patient with severe asthma: any one feature is enough (BTS/SIGN). HSE NCP also lists bradycardia as a life-threatening sign.

• Oxygen: give controlled supplementary oxygen to hypoxaemic patients; aim SpO₂ 94–98% (BTS/SIGN). Do not delay oxygen if oximetry is not yet available; start SpO₂ monitoring as soon as possible.
• β₂ agonist early and in high dose: mild/moderate — pMDI + spacer, titrate to response (HSE pathway: up to 12 puffs); or salbutamol 5 mg via oxygen-driven nebuliser.
• In hospital, ambulance, and primary care, nebulisers for β₂ agonists should preferably be oxygen-driven. Prefer nebuliser (oxygen-driven) if acute severe or life-threatening features are present.
• Give steroids in adequate doses to all patients with an acute asthma attack: prednisolone 40–50 mg orally, or IV hydrocortisone 100 mg if oral not possible (methylprednisolone 125 mg IV is listed in the HSE NCP ED pathway).
• Continue oral prednisolone 40–50 mg daily until recovery (minimum 5 days).
• Repeat salbutamol via spacer or neb at 15–30 minute intervals according to response. If poorly responsive to an initial bolus, consider continuous nebulisation (HSE pathway: salbutamol 5–10 mg/hour with an appropriate nebuliser).
• Pregnancy: treat acute asthma as for non-pregnant patients (including systemic steroids and magnesium if indicated); maintain SpO₂ 94–98%. Acute severe asthma in pregnancy is an emergency — continuous fetal monitoring and early liaison with obstetrics / critical care (BTS/SIGN).

• Call for senior / ICU / specialist help immediately if any life-threatening features are present. Keep the patient accompanied by a nurse or doctor (HSE NCP).
• Add nebulised ipratropium bromide 0.5 mg (4–6 hourly) to β₂ agonist treatment for acute severe or life-threatening asthma, or poor initial response to β₂ agonist (BTS/SIGN / NCEC).
• ABG if SpO₂ <92% or other life-threatening features. Markers of severity: “normal” or raised PaCO₂, PaO₂ <8 kPa, low pH (or high H⁺).
• 12-lead ECG if life-threatening features, arrhythmia, or cardiovascular compromise (HSE NCP ED pathway).
• Consider a single dose of IV magnesium sulphate 1.2–2 g over 20 minutes for acute severe asthma (PEF <50% best or predicted) with poor initial response to inhaled bronchodilators. Use only after discussion with senior medical staff (BTS/SIGN). Irish ED pathways often use 2 g.
• Nebulised magnesium sulphate is not recommended in adults (BTS/SIGN).
• Correct fluids and electrolytes, especially hypokalaemia (HSE NCP; β₂ agonists and steroids can lower K⁺).
• Reserve IV β₂ agonists for patients in whom inhaled therapy cannot be used reliably.
• Do not sedate acute asthma patients unless required for anaesthetic or intensive care procedures.
• Routine antibiotics are not indicated unless there is clear evidence of bacterial infection.

• Repeat PEF after bronchodilator and at intervals thereafter; chart response.
• Continuous pulse oximetry while acute; aim SpO₂ 94–98%. SpO₂ guides need for ABG.
• Bloods: FBC, U&E (watch K⁺), consider CRP if infection suspected.
• CXR is not routinely recommended unless: suspected pneumomediastinum or pneumothorax; suspected consolidation; life-threatening asthma; failure to respond satisfactorily; or requirement for ventilation (BTS/SIGN).
• Monitor for exhaustion, rising PaCO₂, falling SpO₂, and deteriorating PEF: these trigger ICU referral.

• Admit any feature of a life-threatening or near-fatal asthma attack (BTS/SIGN / NCEC).
• Admit any feature of a severe asthma attack persisting after initial treatment (BTS/SIGN / NCEC).
• Irish NCEC: also admit if PEF is <75% best or predicted after initial treatment.
• Patients whose PEF is >75% best or predicted one hour after initial treatment may be discharged from ED unless other reasons favour admission (BTS/SIGN), e.g. still significant symptoms; concerns about adherence; living alone / socially isolated; psychological problems; physical disability or learning difficulties; previous near-fatal asthma; attack despite adequate oral steroids pre-presentation; presentation at night; pregnancy (NCEC / HSE NCP list).
• GPs: refer to hospital anyone with features of acute severe or life-threatening asthma (NCEC / HSE).
• Refer to ICU any patient needing ventilatory support, or acute severe/life-threatening asthma failing therapy (deteriorating PEF, persisting/worsening hypoxia, hypercapnia, falling pH / rising H⁺, exhaustion/feeble respiration, drowsiness/confusion, respiratory arrest). Accompany ICU transfers with a doctor able to intubate.
• If life-threatening features were present, Irish pathways advise admit for a minimum of 24 hours with close observation.

• If nebulised β₂ agonist was given before arrival, consider an extended observation period before discharge. Consider delaying discharge until 08:00 if after midnight (HSE NCP).
• Continue prednisolone 40–50 mg daily until recovery (minimum 5 days). Ensure supply of inhaled corticosteroid and reliever; check inhaler technique. Provide PEF meter advice and a written personalised asthma action plan where possible (BTS/SIGN / HSE NCP).
• Inform the patient’s GP / primary care practice within 24 hours of discharge from ED or hospital (BTS/SIGN). Fax or email the discharge letter where possible (HSE NCP).
• GP clinical review within 2 working days of presentation for moderate / severe / life-threatening attacks; within 2 weeks if mild (HSE NCP discharge bundle).
• After admission with a severe attack, arrange respiratory specialist follow-up for at least one year. Keep near-fatal asthma under specialist supervision indefinitely (BTS/SIGN). HSE NCP also advises asthma/respiratory service follow-up within 4 weeks after ED/hospital presentation.
• Consider psychosocial factors before discharge; low threshold to admit if unsafe to go home.

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